Touchpad has been widely applied in various electronic products, such as hand-held computer, personal digital assistant (PDA), mobile phone, and other electronic systems. A touchpad is used for an input device for a finger or conductive object to slide or touch thereon to control a cursor in relative movement or absolute coordinate movement, or to support other extended functions, for example key or button simulation.
For a touchpad to support more extended functions, a technique of region division has been proposed. For the purpose of providing better operational environment, all of the current computer systems and hand-held devices have adopted window interfaces, and these window interfaces all have evolved to operate in a scroll environment. Conventional touchpads have also provided the corresponding function for scroll control of a window on a computer system. FIG. 1 shows a conventional touchpad 10, on which three regions are divided for a cursor control region 12, a vertical scroll region 14, and a horizontal scroll region 16. When a user slides his finger 18 on the cursor control region 12, the cursor on a corresponding window will move. Sliding the finger 18 on the vertical scroll region 14 causes a corresponding window to scroll upward or downward. Also, sliding the finger 18 on the horizontal scroll region 16 causes a corresponding window to scroll leftward of rightward. The further detail operations of such touchpad are referred to U.S. Pat. Nos. 5,748,185 and 5,943,052.
However, the extended functions will not be executed unless the user touches the predefined corresponding regions since the region division of the touchpad 10 is explicit. For example, if there is a need to execute the vertical scroll function, the finger 18 must slide within the vertical scroll region 14. When the finger 18 slides from the vertical scroll region 14 into the cursor control region 12, the touchpad 10 stops the vertical scroll function since it recognizes that the user desires to execute the general cursor control function by detecting the location of the user's finger 18. Besides, a continuous movement can only define a scrolling direction, such as vertical scrolling direction. If the user desires to execute the horizontal scroll function, he must shift his finger 18 to the horizontal scroll region 16 first. That causes inconvenience of use.
Accordingly, it is desired a control method for executing scroll function in any position of a touchpad.